Adria, Servant of Terror

Whenever you discard a card, surveil and put a Terror counters on Adria.

At the beginning of your end step, remove all Terror counters from Adria. Each player mills that many cards. If you have no cards in hand, you may cast an instant or sorcery spell milled this way by paying life equal to its mana value instead of its usual cost. If it would be put into the graveyard this turn, exile it instead.

Partner with Leah, Vessel of Hatred